Last Thursday, 4,500 families celebrated as they received letters stating their children’s acceptance into one of the open pre-K seats in public schools.

In a June 5 press conference, Mayor Bill de Blasio announced that acceptance and rejection letters had been sent out to parents across the city for the new full-day program, which the mayor has made one of his top priorities in office.

“We know there's going to some really happy families today,” de Blasio said. “We know there's going to be other families who are looking for the next step in the process and the next opportunity.”

For those families, an application for community-based options was included in the same envelope as the pre-K letter.

“I'm going to keep saying it all through the rest of the school year,” the mayor said. “We want parents to apply for any and all of the community-based options that make sense for them.”

De Blasio said that nearly all of the 4,500 spots in public schools have been accounted for, with 41,000 parents applying for the spots, a 35 percent increase from last year.

A hopeful parent, Delnaye Cadogan, was invited to the press conference at P.S. 203 Floyd Bennett School in the Flatlands to open a letter regarding the future of his daughter, four-year-old Odianne.

"Thank you for submitting a pre-K application to the New York City Department of Education,” read the letter. “We are pleased to offer your child free pre-K placement at the following program for 2014-15 school year."

“This is the real thing, the genuine article, and that is the beginning of a world of opportunity for this beautiful young lady,” de Blasio said. “It is an exciting day.”

“I work in New York as a security guard, and the reason for that is to have my children get a good education and a better life,” Cadogan, who hails from the Caribbean, said. “And nothing is more important to me than to make sure that they get that. My reason for coming here today is because of the program that the mayor has introduced, and I am pleased with it.”

Odianne will now attend pre-K at Floyd Bennett School in the fall. Floyd Bennett used to have 36 full-day pre-K spots. With the expansion, it will now offer seats to 72 children.

In total, 20,000 full-day pre-K spots are being offered in public school buildings. Additionally, there are 25,000 community-based seats currently in the application process.

Council member and former educator Alan Maisel commended the mayor for his work in the preschool program.

“I want you to know — I really feel this, very, very profoundly — that, eight years from now, when your administration becomes a part of the history of New York City, this pre-K move will probably be the most significant thing that any mayor could do,” Maisel said.

“You’ll have had more effect on the lives of the people of our city in putting four-year-olds into a pre-K program than almost anything that could be done. So, I thank you very much.”

Not all news was good news, though, when the mayor admitted that overcrowding has continued to be a problem with the pre-K program.

“The overcrowded districts in the traditional public schools are obviously a challenge because we don't have as much space to play with, by definition,” he said, citing central Queens as an example.

“That's an area where I think you're going to find more demand than can be accommodated locally, and people are going to have to think more about whether they want to go a neighborhood or two away, whether they want to find a seat closer to their work, perhaps,” he said.

Among the public school pre-K programs, 45 percent of applicants were matched with their first choice and an additional 18 percent were matched to one of their other ranked choices. Thirty-seven percent of applicants could not be matched to a program.